Angiogenic action of gliostatin in rheumatoid arthritis and its molecular mechanism

在类风湿关节炎(RA)的病理组织学中，滑膜细胞的新生血管、增殖以及单核细胞的涌入和激活是滑膜关节的特征事件。我们以前已经检测了RA患者血清和滑液中血管生成因子胶质抑制素(GLS)的浓度，并首次发现RA滑液和RA血清中都有极高的浓度。此外，我们先前的研究表明，GLS作为一种细胞因子，通过自分泌机制在RA患者的成纤维细胞样滑膜细胞(FLSS)中增强自身的合成。值得注意的是，GLS还可诱导和分泌基质金属蛋白酶(MMP1)和MMP3，从而触发软骨退变。最近，我们报道了兔膝关节内注射rHuGLS诱导的类风湿性滑膜炎。本研究的目的是探讨GLS/TP是否参与了类风湿关节炎(RA)血管生成细胞因子血管内皮生长因子(VEGF)的调节。培养RA患者成纤维细胞样滑膜细胞，用重组人GLS(RHuGLS)和白介素1β刺激。免疫组织化学显示滑膜衬里细胞中可检测到GLS/TP和血管内皮生长因子。经rHuIL-1β处理后，培养的FL细胞中VEGFm RNA和蛋白水平均显著升高。RHuGLS以剂量依赖方式增加血管内皮细胞生长因子mRNA的表达。我们在经rHuGLS(300 ng/ml)处理的FL的培养上清液中检测到高浓度的VEGF165蛋白，这与RA患者滑液中的GLS水平相当。提示GLS/TP与VEGF在类风湿滑膜炎血管生成中具有协同作用，GLS/TP对血管生成有调节作用。

Neovascularization, proliferation of synovial cells, and mononuclear cell influx and activation are characteristic events observed in synovial joints in the pathohistology of rheumatoid arthritis (RA). We have previously measured the concentration of the angiogenic factor, gliostatin (GLS), in sera and synovial fluids of RA patients, and demonstrated for the first time an enormously high concentration in RA synovial fluids as well as in RA sera. Furthermore our previous study demonstrated that GLS acts as a cytokine to augment its own synthesis in fibroblast-like synoviocytes (FLSs) obtained from patients with RA through an autocrine mechanism. It should be noted that GLS additionally caused induction and extracellular secretion of matrix metalloproteinase (MMP)-1 and MMP-3 triggering cartilage degeneration. Recently we reported that intraarticular injection of rHuGLS to rabbit knees induced RA-like synovitis.The purpose of this study was to elucidate whether GLS/TP is involved in the regulation of the angiogenic cytokine vascular endothelial growth factor (VEGF) in rheumatoid arthritis (RA). Fibroblast-like synoviocytes (FLSs) from patients with RA were cultured and stimulated with recombinant human GLS (rHuGLS) and interleukin (IL)-1β. Immunohistochemistry showed that GLS/TP and VEGF were detectable in the synovial lining cells. In cultured FLSs, both VEGF mRNA and protein levels were markedly increased by rHuIL-1βtreatment. rHuGLS increased VEGF mRNA expression in a dose-dependent manner. We detected high concentrations of VEGF165 protein in culture supernatants from FLSs treated with rHuGLS (300ng/ml), which were comparable to GLS levels found in synovial fluid of RA patients. These findings indicate that GLS/TP and VEGF have synergistic effects on angiogenesis in rheumatoid synovitis, and that GLS/TP has a role in regulating VEGF.